This proposal seeks to acquire a state-of-the-art multimodal microscope that will enable visualization of biological tissues at very high resolution without the need to section them. One of the imaging modalities, coherent anti-Stokes Raman scattering (CARS) microscopy, has emerged as a unique non-invasive visualization tool for monitoring changes in the lipid and mineral composition of biological samples. The ability to study these aspects of the samples in combination with surrounding cellular and extracellular components will have a significant impact on a wide range of important biomedical problems, such as diabetes, cardiovascular disease, obesity, cancer, and brain function. Thus, there are important potential societal benefits. In addition, this will be a unique shared resource facility for Tufts University and will be made available to the broader academic and industry community of the Boston area for research purposes. Finally, this microscope will serve as an outstanding educational tool that will be incorporated in laboratory courses and workshops to train undergraduate and graduate students as well as other members of the academic and research community.
The proposed multi-modal confocal/two-photon/ CARS microscope will be used to address key questions in which dynamic changes in the mineral, lipid and potentially water content of biological tissue specimens in response to interactions with their surrounding environment play a key role. One of the main properties of CARS that enables these studies is its ability to provide strong, chemically specific signals without the need for exogenous dyes. The latter may be tedious or impossible to incorporate in a three-dimensional specimen or the agent specificity may change over time leading to artifacts. CARS also offers inherent optical sectioning capabilities, needed to examine in vitro, ex vivo and in vivo tissue specimens. In fact, because of the highly scattering nature of lipids, CARS is needed for detailed studies of even two-dimensional cell specimens. Finally, compared to confocal Raman for example, CARS offers superior signal to background, which in turn enables fast imaging. As a result, we expect that the requested CARS microscope will provide important insights in: a) identifying and monitoring distinct adipose tissue type depots in response to anti-obesity interventions, b) understanding the effects of different engineered extracellular matrices and bioelectric signaling mechanisms on neuronal growth and repair, c) regulating lipid droplet dynamics, metabolism and obesity, d) understanding lipidoid-mediated biomacromolecule delivery, d) dental tissue development and regeneration, e) mineral deposit accumulation during calcific aortic valve disease, f) adipose cell-matrix interactions during breast cancer development and in response to novel treatments, and g) characterization of the pericellular brush of cancer cells.
